Poly(methyl methacrylate), commonly referred to as acrylic or acrylic glass, is a substance that has supplanted glass in a lot of ways already.For instance, it is used for the spectator shields in ice hockey rinks, the visors of motorbike helmets, for bathyscape windows and aquaria, and for various other items that demand a more durable, crack-resistant material than glass still endowed with the transparency needed to facilitate usage.In this sense, acrylic certainly fits the bill.This thermoplastic material is extremely tough despite its transparency and is far harder to break than glass.Even cracks are rare with acrylic, and they happen only in situations where extreme force and powerful impact are applied.Hence, consumers are now wondering why automobile manufacturers still insist on using glass for cars, when a material like this is available.

The truth is that acrylic also has its weaknesses.First of all, it is more expensive.This is not actually because of its prestige but rather because of the difficulty of shipping it.Glass is actually far more easily shipped because it takes fewer scratches with moderate impact or rough handling.Acrylic, even if it costs very little to make, is terrifically sensitive to rough usage.Yes, it is durable, which means it shall take far more to break an acrylic sheet than it would to break a glass pane.However, its clarity is very easily compromised.

This also means that acrylic is avoided by automobile manufacturers due to its propensity to take scratches and scrapes with each use.There are in fact some automobiles that use acrylic—certain cars used for NASCAR and similar vehicle races use acrylic windshields.However, these are also replaced after every use, because of the resulting scratches after a race.To keep the old ones would be dangerous because the scratches are often bad enough to impede driver vision.

Another reason glass is still to be preferred over acrylic is that acrylic tends to get discolored over time.Granted, some shall note that this may be a problem with glass windshields on occasion—but the actual cause of discoloration in such cases is not the material of the windshield in itself, but rather the material that you place on the windshield.That is, most discolored or yellowed windshield glass is not actually yellowed because the glass has changed color: the discoloration comes from such things as badly applied or old tint jobs, chemical accumulation on the glass surface, stains caused by acid rain and hard water, etc.These are things that may yet be fixed by an auto glass repair specialist.Acrylic, on the other hand, normally becomes discolored due to exposure to the sun, which triggers a chemical reaction in the acrylic material itself.This cannot be avoided easily and is also irreparable.